Hydraulic vane apparatus



Nov. 5,. 1963 Filed Aug. 4, 1958 C. A. BAKER HYDRAULIC VANE APPARATUS 9 Sheets-Sheet l INVENTOR. CHARLES A BAKE R ATTORN EY Nov. 5, 1963 c. A. BAKER 3,109,381

HYDRAULIC VANE APPARATUS Filed Aug. 4, 195a 9 Sheets-Sheet 2 20 H6 24 I3I |6l 26 48 22 INVENTOR. CHARLES A. BAKER ATTORNEY Nov. 1963 c. A. BAKER HYDRAULIC VANE APPARATUS 9 Sheets-Sheet 5 INVENTOR. CHARLES A,BAKER BY w 1' ATTORNEY Nov. 5, 1963 c. A. BAKER HYDRAULIC VANE APPARATUS 9 Sheets-Sheet 6 Filed Aug. 4, 1958 VON OWN

INVENTOR. CHARLFS A .BAKER BY w! ATTOR NEY.

c. A. BAKER HYDRAULIC VANE APPARATUS 9 Sheets-Sheet 8 Filed Aug. 4, 1958 INVENTOR. CHARLES A. BAKER raw J ATTO RN EY United States Patent 3,199,331 HYDRAULTC VANE APPARATUS Charles A. Baker, R31). 1, Canister), N.Y. Filed Aug. 4, 1958, 8st. No. 752,3ti6 A. Eim'ms. (c1. ros -12s This invention relates to a hydraulic motor and pump or the like, and more particularly to a rotary variable volume vane pump and motor and controls therefor.

The invention more especially has to do with a variable volume hydraulic rotary vane apparatus wherein the rotor assembly within the system cooperates with the housing structure to provide a control piston assembly eapable of shifting the piston assembly to control the volumetric and pressure output when employed as a pump, or the output speed and torque when employed as a motor.

The above and other novel features of the invention will appear more fully hereinafter from the following detailed description when taken in conjunction with the accompanying drawings. It is expressly understood that the drawings are employed for purposes of illustration only and are not designed as a definition of the limits of the invention, reference being had for this purpose to the appended claims.

[In the drawings wherein like reference characters indicate like parts:

FIGURE 1 is a longitudinal sectional view of the apparatus in one form wherein certain of the moving parts are disposed externally of the piston assembly;

FIGURE 2 is a longitudinal sectional view taken on the line 2-2 of FIGURE 1;

FIGURE 3 is a fragmentary transverse sectional view taken on the line 3-3 of FIGURE 1;

FIGURE 4 is a transverse sectional view taken on the line 4-4 of FIGURE 1;

FIGURE 5 is a transverse sectional View taken on the line 5-5 of FEGURE 1;

FIGURE 6 is a transverse sectional view taken on the line 6-6 of FIGURE 1;

FIGURE 7 is a longitudinal sectional view of a modified form of the invention wherein the moving parts are within the piston assembly;

FIGURE 8 is a longitudinal sectional view taken on the line 8-8 of FIGURE 9;

FIGURE 9 is a transverse sectional view taken on the line 9-9 of FIGURE 7;

FIGURE 10 is a transverse sectional view taken on the line 10-10' of FIGURE 7;

FIGURE 11 is a transverse sectional view taken on the line 11-11 of FIGURE 7;

FiGURE 12 is a transverse sectional view taken on the line 12-12 of FIGURE 7;

FIGURE 13 is a fragmentary sectional view taken on the line 13-13 of FIGURE 7 showing relief ports;

FIGURE 14 is a schematic control system for the apparatus when employed as a pump; and

FIGURE 15 is a schematic control system for the apparatus when employed as a motor.

Referring to FIGURE 1, there is shown a housing which may be formed of end members and 22 and intermediate members 24 and 26, all of which may be held together by through bolts 28, strategically located as desired. The member 24 is provided with a recess 3 1M381 Patented Nov. 5, 1963 which is generally circular as at 30, and which has arcuate opposed lands 32. Additionally cylindrical recesses 34 and 36 are provided, which are coaxial and of the same radius as the lands 32. Such recesses are adapted to receive cylindrical rolls 38 and 40, each having opposed grooves 42 and 44 spaced 180. The member 26 is provided with a cylindrical aperture 46 in which is disposed a rotary cylindrical sleeve or shroud 48, having an internal cylindrical surface 50 of a diameter bearing a ratio to the diameter of said rolls 38 and 40 of 3 to 2, in the form shown. The surface 50 bears a tangential relationship with the rolls 38 and 46, the diameter of the surface Ell being three-fifths of the spacing between the arcs of the rolls 38 and 40.

The sleeve 48 and the cavity formed by the wall 30, of the member 24, is in effect a fluid pressure cylinder, within which is disposed a piston comprising a rotatable member 54 having a cylindrical exterior 56 of a diameter to closely fit within the shell 48. The rotatable member is provided with three ribs or vanes 58, 6t} and 62 located 120 apart, adapted to mesh with and coact with grooves 42 and 44 of the rolls iih and 4-0, and the internal wall of the sleeve member is provided with mating grooves 64, 6e and 63 to receive said vanes. Iournalled on a hub extension of the rotatable member 54, is a non-rotating member 72, the exterior surface of which is complemental to the recess 3!), and the lands 32 thereof, the arcu-ate grooves 74 of the member 72 being also adapted to closely embrace the portion of the rolls 33 and 4b which project into the cylindrical bores 3i). The hub extension is provided with a collar 76, which may be threaded on the hub. A thrust bearing '78 between the collar and nonrotating member 72 is disposed in the recess 8t of the member 72. An annular face groove is provided with an annular thrust bearing 82 on the opposite side of the member 72 to provide an anti-friction thrust bearing between the non-rotatable member '72 and the rotating member 54.

A shaft 84 enters the casing through the end wfil 22, and is journalled therein, as well as in the end wall 20, and is provided with a splined connection 86 with the rotatable member 54, so that the members 54 and 72 may freely move axially as a unit in the cylinder, the movement being limited by the end wall 20 and the end wall 88 of the sleeve or shell member 48.

The rolls 38 and 40 are afiixed to shafts 9i) and 92 journalled in and extending through the housing member 26, and the ends of such shafits have affixed thereto gear wheels 94 and 96, which mesh with a gear blank as aflixed to the outside of the end wall 88 of the shell or sleeve member 43 as by studs and the gear is keyed to the shafit as at 101. The pitch circles of the gear 93, and the gear wheels 94 and 96 have a ratio of 3-2., and the number of teeth on the respective gear wheels bear a like ratio. The sleeve member 48 need not be rigidly fixed to the gear 98, or may be left free of the gear. In such case the sleeve is allowed to float, rotating with the rotor 54, without strain.

A thrust bearing 104 is provided between the end wall 22 and the gear blank 98. Control fluid. such as oil is admitted to the chamber 1% through a port 103 in the casing end wall 24). Control fluid such as oil is also admitted to the chamber through a series of ports 112 0.3 in the shell end wall 88, and gear 98, and the port 114 in the end wall 22. The position of the piston may be varied by differential pressure in the chambers 106 and 110.

The cylindrical bore 30 is provided with keyways 116 and 1 1-8, and the head end of the non-rotating member 72 is provided with keys 120 projecting into said grooves, and the end wall 20 is provided with clearance recesses 122 for the keys. A cam bar 126 afixed to the nonrotating member 72, and projecting through a stufiing gland 123 in the end wall 20 is provided to indicate the position of the piston assembly at any time. Such bar 126 is provided with a cam face 130, adapted to actuate a follower member 129 whereby automatic controls referred to hereinafter may be employed. Seal rings 131 and 133 are provided in the cavity wall of casing member 24, and the end of the piston member 54 respectively. The latter seal is provided with projections 135 mating with and sealing the grooves 64, 66 and 68.

Ports 134, 136 138 and 140 lead to cavities 1142, 144, 146 and 148 adjacent to the contact area of the rolls 38 and 40 with the member 54. Such cavities have an axial length corresponding to the length of the rolls 38 and 40. If rotation of the member 54 is in the direction of arrow A, and rotation of rolls 38 and 40* is in the direction of arrows B, the assembly will act as a hydraulic motor if oil under pressure is delivered to conduits 136 and 140, conduits 134 and 138 acting as exhausts. If power is applied to the shaft 84 to rotate the member 54 in the direction of arrow A, then the device acts as a pump delivering fluid under pressure through conduits 134 and 138, conduits 136 and 140 then acting as intakes.

The volume of the pump or the speed or torque of the motor may be varied by shifting the piston assembly within the cylinder. The assembly is shown in mid position and the annular cavity, or the effective length of the vanes 58, 60 and 62 is the distance between the end face 150 of the shell 48 and the end face 152 of the nonrotatable piston member 72 (see FIGURE 1). Movement of the piston assembly to the right decreases the volume, and if acting as a pump, the output is decreased. If acting as a motor, the speed is increased and the torque reduced for a given pressure input. Movement of the piston to the left increases the output when operating as a pump for a given speed, and decreases the speed with an increase in torque when operating as a motor.

The rotor 54 and drums 38 and 40 have been shown with a diameter ratio of 3 to 2. Various ratios may be selected as desired. The drums 38 and 40', for example, could be one-half the diameter shown and provided with a single groove, and in such case the drums would rotate at double the velocity. The drums 38 and 40 may be of the same diameter as the rotor and rotate at the same speed and be provided with three grooves. Various combinations may be employed as will be readily understood. While the piston assembly has been shown splined to the shaft, for control by differential pressure, the rotor 54 of the piston assembly may be fixed to the shaft, and the position of the assembly can be varied mechanically by shifting the shaft, or the assembly can be moved by applying axial pressure in either direction to the cam bar to shift the assembly. If the shaft be shifted for control, the key 101 to gear 98 will take the form of a spline.

In the internal arrangement shown, the casing 200 has a drive shaft 202 extending therethrough, to which is keyed a sleeve member 204, closed at one end as at 205, that is rotatably disposed within the housing and which may be referred to as the rotor. There is provided a bearing 206 coacting between the housing and sleeve 204. The rotor 204 is provided with three internal vanes 208, which mesh with the grooves 210 in the drums 212. The drums and grooves 210 have the same length as the vanes 208. The drums 212 are fixed to their respective shafts 214, which are journalled in a piston 216, that is slidably disposed within the housing 200. One end of the housing, internally,-is generally cylindrical as at 218, there being provided arcuate bays 220 of a radius to closely receive the cylindrical drums 212. The cylindrical portion 218 and the bays 220 extend to the end 228 of the sleeve member or rotor 204 at which point the internal diameter of the housing 200 increases to receive the rotor as at the annular shoulder, indicated at 221. Keyways 222 receive key-like projections 224 on the left hand end of the piston 216, to prevent rotation of the piston 216 in the casing 200, and the head end 226 of the block 216 is shaped to slide in the cylindrical portion and bays. A suitable seal 230 is provided to prevent leakage.

T he piston 216 may be made up of three parts dividing on parallel planes extending through the axes of the shafts 2 14. The outer parts 217 and 219' are affixed to the central member 215 of the piston 216, as by studs as indicated at 213. The parts 215, 217 and 219 have suitable cavities conforming to and adapted to receive the shafts 214 and their respective drums 212.

The other end of the piston 216 is provided with a cylindrical bearing support 232, about which is journalled a sleeve 234, the external surface 236 of which includes three vane grooves 235 and is complemental to the internal surface 209 and vanes 208 of the left hand end of sleeve 204. A seal ring 238 having three teeth is provided.

The sleeve 234 may be provided with thrust bearings 237, disposed between collars 239 aflixed upon the bearing support 232 of the piston 216. The sleeve 204 is provided with elongated internal gear teeth 240 that are adapted to mesh with pinions 242 aflixed to the ends of each of the shafts 2114. The pinions have one-third the number of teeth of the internal gear 240 to assure coordination between the rotation of drums 212 and the sleeve 204 so that their respective grooves 210 and the vanes 208 will always mesh.

The ratio of 3 to 1 is not necessary except in the form shown. Any ratio may be used as long as the small gears 242 can be contained within the large gear 240- and provide the proper ratio in respect to the number of vanes 208 used in member 204 and the corresponding number of grooves 210 in drums 212.

V The sleeve 232 is provided with a reduced external diameter portion 241 to clear the teeth 240.

It will be seen from the foregoing that the piston 216 with its drums, sleeve 234, and pinions are slidable as a unit within the sleeve 204 and the casing 200. As shown, the unit is located slightly to the left fromone end of its length of travel, which length cannot exceed the length of the drums 212. As shown, the cross section of the effective length of each vane 208 is the product of the radial height of the vanes 208 and the portion thereof telescoped within the grooves 210. It will be understood that the portion telescoped may be increased by movement of the piston unit to the right or decreased approaching zero by movement of the unit to the left thus varying the effective length of the vanes 208. By moving the piston assembly, the volume of the pump or motor is increased or decreased.

It will be seen that the peripheral chambers swept by the vanes 208 are formed by the annular shoulder 221, which is interrupted only by the drums 212, the end face 243 of the sleeve 234, the portion of the internal cylindrical'surface of the rotor 204 that is exposed between shoulder 221 and the end face 243, and the portion of the external cylindrical face of the piston, lying between the shoulder 221, and end face 243, such surface being interrupted at diametrically opposite points by the drums 212.

The sleeve 204, at the left hand end, is provided with a multiplicity of radial ports 245 disposed in a plurality of rows extending parallel to the axis, and uniformly spaced around the circumference thus providing axially spaced circumferential rows. The rows are limited in length axially by the length of the vanes 208. The housing has inlet and outlet cavities 246 and 248 of an axial width to embrace the ports of each axial row, and at least two such rows circumferentially. The cavity 246 and adjacent cavity 243 on each side are spaced circumferentially by a distance greater than the circumferential distance between adjacent rows of ports 245, to prevent possible bypass.

The ports 245, except when opposite the cavities 246 and 248, are blocked at their end by the sealing effect of the cylindrical internal Wall of the housing 260. The cavities 246 and 248 lead to inlet and outlet connections 247 and 249 in the bosses 251. and 253.

To provide relief when the grooves 210 and vanes 208 commence to mesh and immediately thereafter, small ports 269 and 262 connecting the arcuate corner 261, formed by the arcuate bays 220 and shoulder wall 221, are provided, as shown in FIGURE 13. Such ports extend to the cavities 24d and 243 respectively. The ends of said ports are normally closed oif by the cylindrical periphery of the drum 212, and the end face 223 of the sleeve 204.

Referring to FIGURES 14 and there is shown diagramatically the internal apparatus of FIGURES 7-13, although the same control may be applied to the form of FIGURES 1-6 as will readily appear. In each form of the hydraulic pump or motor, the piston assembly, 54 and '72 of FIGURE 1, and 216 of FIGURE 7 is moved by varying the relative pressures in the end chambers such as 1% and lift through admission or exhaustion of hydraulic fluid through the end ports 1% and 114. Movement of the assembly 21a is reflected by the movement of the pin 3% in FIGURE 7, and movement of the corresponding pin 129 in the form of FIGURE 1, which constitute follow up means. With rotation of the parts in both forms in a clockwise direction as shown, (except FIGURE 6) the ports 134 and 133 of FIGURE 1 are pressure output, when operating as a pump, and the ports 249 of the form in FIGURE 7, see FIGURE 11, are pressure output. The ports 1% and 14b of FIGURE 1 are intake ports, and the ports 247 are also intake ports during such operation.

When acting as a motor, the intake ports aforesaid of FIGURE 14 are pressure input ports, in FIGURE 15 and the pressure output ports of FIGURE 14 become exhaust ports in FIGURE 15, rotation being in the same direction. The ports 134 and 138 will be connected together, and the ports 136 and 14d will be connected together, and the same is true of the two ports 247 and the two ports 249, which are connected together as shown diagramatically in FIGURES 14 and 15, by the conduits d and 3&2.

The control shown in FIGURE 14 is for operating the apparatus as a pump, either as a constant volume pump, manually controlled, or a constant pressure pump automatically controlled. For the purpose, a manual rotary control valve 394 is provided which may be turned to the left for constant volume output, and to the night for constant pressure output. Movement of the control valve 3% to the right, to the constant pressure position, is resisted by a lever 38-6, fulcrummed at 3%. The lever engages an arm 309 projecting from the valve rotor 310, and urges the valve to the neutral position shown from the constant pressure position by action of the compres sion spring 312.

A floating equalizer bar 314 is provided, having one end yieldingly supported as at 318, and its other end actuated by the pin 3% in response to movement of the piston assembly 216. The equalizer bar is urged downwardly inwardly of its yieldingly supported end by the piston of a pressure cylinder 320, acting through a rod 322, and movement of the equalizer bar intermediate the rod 322 and pin see, either up or down, actuates a threeway control valve 324, to admit fluid under pressure into the chamber 1%, or the chamber 114 through conduits 1% and 114 respectively.

Assuming that it is desired to maintain constant pressure output automatically, with the motor M driving the pump at uniform speed, the control 304 is moved to the right. The pump output pressure is thereby connected through conduit 304) through the valve port 326 to the conduit 328 leading to the cylinder 320. As pressure increases in the output, the piston rod 322 is urged downwardly against the spring 321, shifting the valve 324 downwardly to admit fluid to the chamber to move the assembly 216 to the left, and decrease the volume output, with a resulting drop in pressure. As the assembly moves to the left, the pin 300 lifts the end of the equalizer bar, raising the valve 324 to cut off the further supply of fluid to the chamber 110. Should the pressure drop, the spring 321 will move the rod upwardly, the pressure in cylinder 320 having decreased, and cause the valve 324 to apply pressure to the end chamber 106 to move the assembly 216 to the right and thereby increase the volume output and restore the pressure, the pin 3M lowering as the assembly moves to the right to return the valve 324 to the neutral position, which will be hastened by the increase in pressure in the cylinder 329. The degree to which the control 304 is moved to the right, varies the pressure on the spring 321, and thus the further the control 3% is moved to the right, the higher will be the constant pressure output.

If it is desired to provide constant volume output, movement of the control 364 to the left, relieves the cylinder 32%) of pressure by connecting the line 328 to the intake line. The arm SE99, acting through lever 3 30 fulcrummed as at 332, will lift the rod 322, and lift the valve 324 to admit fluid to the end chamber 1% to increase the volume. As the assembly 216 moves to the right the cam lowers the pin 3%, and neutralizes the valve 324. If a further increase in volume is desired the control lever 304 may be moved further to the left. If a decrease is desired, reverse movement of the control lever 3% decreases the upward pressure on the spring 321, lowering the equalizer bar 314 to lower the valve 324 to admit fluid to the chamber 119 and thus move the assembly to the left, and decrease the volume.

In the system shown in FIGURE 15, wherein the apparatus operates as a motor, assuming a source of constant volume and pressure, be supplied at P to the line 3&2, movement of the control 3&4 to the right will apply pressure to the cylinder 320, which will in turn move the valve 324 downwardly to shift the assembly 216 to the right to decrease speed. The assembly on moving to the right lifts the pin 3% to neutralize the valve 324. Further movement of the control 394 compresses the spring, tending to raise the valve 324, and move the assembly to the left to increase speed, the pin 300 lowering to ne11- tralize the valve 324. If a constant speed is required, subject to manual control, movement of the control 3G4 to the left, relieves cylinder 32%) of pressure. Movement of the control to varying degrees to the left raises or lowers the rod 322 to raise or lower the valve 3924. Upon lifting the valve 324, pressure is delivered to the chamber 11%, to move the assembly to the left to increase speed. Movement of the assembly to the left raises pin 3% to neutralize the valve 324. Thus the speed is varied by the degree of movement of the control 3614 to the left.

It will be seen that the control 364, acting either directly on the rod 321, or aided by pressure in the cylinder, provides with the follow up in 36th, a differential actuation of the valve 324.

In both forms of the invention it will be seen that there is a member 54 or 2% having vanes thereon which may be referredto as the rotor, a shield or shroud member such as 43, or 234 which rotates and which is complemental to and adapted to telescope over the rotor, on relative axial movement between the two to change the active exposed portion of the rotor vanes, and that there are rotary abutments 33 and 49, or 212 and 212, which in either modification are located axially adjacent .rotation of the rotor.

' the shield or shroud, and which have rolling contact with a portion or all of the rotor, and grooves 42 and 44, or 21%, 210 adapted to receive the rotor vanes on rotation thereof past the rotary abutments and each form have means for rotating the rotary abutments in timed relation to the The rotor 54 has a non-rotary back up plate 72 whose axial spacial relationship with respect to the rotor remains constant, and which has a clearance grooves 32 for the rotary abutments 38 and 40. Similarly the rotor 204 abuts against the annular face 221 of the casing 200 which face constitutes a back up plate, and the inside wall of the casing is provided with arcuate bays 220 to receive the rotary abutments 212. Thus in the arrangement of FIGURES 1-6 inclusive, the piston assembly comprises the rotor 54 and back up member 72, and move relatively to the rotary abutments 38 and 40 and shield 48, which are mounted in the cylinder casing structure whereas in FIGURES 7-13 inclusive the rotor and back up member are in effect the cylinder or casing, and the piston is comprised of the shield or shroud 234, and the rotary abutments 212.

The axial position of the piston assembly in reference to the casing assembly in either modification determines the active length of the vanes of the rotor.

The pump with the control of FIGURE 14, is adapted to be connected to the motor of FIGURE 15 by connecting the pump pressure output to the motor pressure input. It will be seen that a pump of the type described, Whose pressure output is connected to the pressure input of a motor of the type described, with the pump output controlled manually at a constant pressure, and the motor controlled automatically at constant pressure, will transfer energy to the motor at a substantially constant rate, providing an infinitely variable speed torque output of the motor.

Although several embodiments of the invention have been illustrated and described, it is to be understood that the invention is not limited thereto. As various changes in the construction and arrangement may be made without departing from the spirit of the invention, as will be apparent to those skilled in the art, reference will be had to the appended claims for a definition of the limits of the invention.

What is claimed is:

1. A rotary vane variable volume hydraulic displacement apparatus, comprising a casing having an internal cylindrical cavity, a rotatable sleeve in one end thereof having a cylindrical surface, a piston assembly reciprocatable within said cavity and sleeve, having a memotatable element and a rotatable element having a cylind'rical surface, the latter telescopically disposed within said sleeve, complemental vane and groove means on the surfaces of said rotatable element and sleeve, eccentrically mounted rotatable cylindrical members grooved to mesh with said vane means tangentially disposed in respect to the cylindrical surface of said rotatable element, and driven in timed relation thereto, and means for admitting fluid pressure into said cavity and sleeve on opposite sides of said piston assembly to apply fluid pressure directly to the opposite ends of the non-rotatable and rotatable elements of the assembly for hydraulically moving said piston assembly axially within said casing to vary the effective length of said vane means, said means including a three-Way valve adapted to admit fluid pressure to said casing at one end or the other to move said piston assembly in one direction or the other, follow up means actuated by axial movement of said assembly in respect to said casing, control means, and means for actuating said valve in response to the diflerential actuation of said follow up means and said control means.

2. A rotary vane variable volume hydraulic displacement apparatus comprising, a casing having an internal cylindrical cavity at one end, a rotor within said cavity having a cylindrical exterior of lesser diameter than said cavity and having a plurality of vanes disposed in equally spaced relation around its periphery of a radial height to sweep a portion of said cavity, cylindrical recesses in said casing disposed tangentially in respect to the cylindrical rotor exterior, drums having cylindrical walls disposed in said cavities, said drums having elemental grooves in their exterior complemental to said vanes, inwardly extending arcuate lands formed in said cylindrical cavity in axial alignment with said drums and of a radius corresponding to the radius of said recesses, said lands extending from said drums toward one end of the cavity, an annular enlargement of said cavity extending from said drums to the other end of said cavity, an annular shroud rotatably mounted in said annular cavity having an inner surface complemental to said rotor and said vanes, and adapted for relative telescopic movement therewith, a non-rotatable piston member disposed adjacent the land side of said rotor and having an exterior contour complemental to said cylindrical cavity and the lands therein, means for keying said piston member against rotation, thrust bearing means for securing said piston member for axial movement with said rotor, and means for driving said drums from said shroud at a speed correlated to the speed of said rotor and shroud and dependent on the relative diameters of said rotor and drums, and the number of vanes and grooves thereof.

3. A rotary variable volume hydraulic displacement apparatus comprising a casing cylinder assembly, and a piston assembly mounted therein for axial movement relative to the casing assembly, one of said assemblies having a vaned rotor and a nonrotating back up surface in end abutting relation to the rotor, and the other assembly having an annular shield complemental to and adapted to telescope over varying portions of said vaned rotor, to vary the exposed extent of said rotor, and an annular wall swept by the exposed portion of said vanes and having rotary abutment members projecting radially therethrough, said abutment members having vane receiving grooves and being adapted to roll upon the exposed portion of said rotor, means for admitting fluid under differential pressure to said casing cylinder assembly at opposite ends thereof to directly apply hydraulic pressure within the cylinder assembly to the vaned rotor and non-rotating backup surface to axially move the piston assembly therewithin to effect variation in the exposed unshielded portion of said rotor, a three-Way valve for admitting fluid under pressure to the opposite ends of said cylinder assembly, and differential means including means responsive to the axial movement of said piston assembly within said cylinder assembly and a manual control for actuating said valve.

4. A rotary variable volume hydraulic displacement apparatus comprising a casing cylinder assembly, and a piston assembly mounted therein for axial movement relative to the casing assembly, one of said assemblies having a vaned rotor and a non-rotating back up surface in end abutting relation to the rotor, and the other assembly having an annular shield complemental to and adapted to telescope over varying portions of said vaned rotor, to vary the exposed extent of said rotor, and an annular wall swept by the exposed portion of said vanes and having rotary abutment members projecting radially therethrough, said abutment members having vane receiving grooves and being adapted to roll upon the exposed pontion of said rotor, means for admitting fluid under differential pressure to said casing cylinder assembly at opposite ends thereof to directly apply hydraulic pressure within the cylinder assembly to the vaned rotor and non-rotating backup surface to axially move the piston assembly therewithin to effect variation in the exposed unshielded portion of said rotor, hydraulic fluid inlet and outlet means for the rotor disposed on eircumferentially opposite sides of each of said rotary abutment members, a three-way valve for admitting fluid under pressure to the opposite ends of said cylinder assembly, and differential means including means responsive to the relative axial movement between said assemblies, and a manual control, for actuating said valve.

References Zita-1! in the file of this patent UNITED STATES PATENTS 11) Carroll Mar. 8, 1949 Vigneau Jan. 19, 1954 Melville Apr. 13, 1954 Heldenbland July 27, 1954 Tobias May 26, 1959 Le Febvre et al Ju=1y 19, 1960 Moore Oct. 11, 1960 FOREIGN PATENTS Great Britain June 18, 1936 

1. A ROTARY VANE VARIABLE VOLUME HYDRAULIC DISPLACEMENT APPARATUS, COMPRISING A CASING HAVING AN INTERNAL CYLINDRICAL CAVITY, A ROTATABLE SLEEVE IN ONE END THEREOF HAVING A CYLINDRICAL SURFACE, A PISTON ASSEMBLY RECIPROCATABLE WITHIN SAID CAVITY AND SLEEVE, HAVING A NONROTATABLE ELEMENT AND A ROTATABLE ELEMENT HAVING A CYLINDRICAL SURFACE, THE LATTER TELESCOPICALLY DISPOSED WITHIN SAID SLEEVE, COMPLEMENTAL VANE AND GROOVE MEANS ON THE SURFACES OF SAID ROTATABLE ELEMENT AND SLEEVE, ECCENTRICALLY MOUNTED ROTATABLE CYLINDRICAL MEMBERS GROOVED TO MESH WITH SAID VANE MEANS TANGENTIALLY DISPOSED IN RESPECT TO THE CYLINDRICAL SURFACE OF SAID ROTATABLE ELEMENT, AND DRIVEN IN TIMED RELATION THERETO, AND MEANS FOR ADMITTING FLUID PRESSURE INTO SAID CAVITY AND SLEEVE ON OPPOSITE SIDES OF SAID PISTON ASSEMBLY TO APPLY FLUID PRESSURE DIRECTLY TO THE OPPOSITE ENDS OF THE NON-ROTATABLE AND ROTATABLE ELEMENTS OF THE ASSEMBLY FOR HYDRAULICALLY MOVING SAID PISTON ASSEMBLY AXIALLY WITHIN SAID CASING TO VARY THE EFFECTIVE LENGTH OF SAID VANE MEANS, SAID MEANS INCLUDING A THREE-WAY VALVE ADAPTED TO ADMIT FLUID PRESSURE TO SAID CASING AT ONE END OR THE OTHER TO MOVE SAID PISTON ASSEMBLY IN ONE DIRECTION OR THE OTHER, FOLLOW UP MEANS ACTUATED BY AXIAL MOVEMENT OF SAID ASSEMBLY IN RESPECT TO SAID CASING, CONTROL MEANS, AND MEANS FOR ACTUATING SAID VALVE IN RESPONSE TO THE DIFFERENTIAL ACTUATION OF SAID FOLLOW UP MEANS AND SAID CONTROL MEANS. 